This invention is related to warning systems, particularly apparatus for quickly signalling when a hydraulic system has sprung a leak.
Many types of equipment use hydraulic systems as the power source for various attachments and for their own component parts. For example, some commercial lawn mowers used to cut the grass on golf course greens use pressurized hydraulic fluid to power the cutting reel and to drive the mower's wheels using individual hydraulic motors at each wheel. One problem with hydraulic systems, which is particularly acute with golf course green lawn mowers, is that if the system springs a leak much damage can be done to the golf green by the hot hydraulic fluid before the operator notices the leak.
There are many types of low fluid level warning systems presently available that can be used to alert the operator of a leak in the system. Such sensors commonly detect when the fluid level drops below a set level. Since hydraulic fluid heats up and expands during use, the reservoir fluid level also rises during use. Therefore the set level must be set at a point below the lowest operating level when the fluid is still cool. If the hydraulic system springs a leak while the hydraulic fluid is cool, the sensor will drop below the set level relatively quickly. However, if the leak occurs after the fluid has heated up and expanded during use, a rather large quantity of hydraulic fluid will be lost before the system provides its warning. With slow or moderate leaks this may or may not be catastrophic for a golf course because the fluid would be spread over a large area. However, if a fast leak occurs on a golf green, a substantial volume of hot hydraulic fluid can be deposited in a relatively small area. This can lead to the destruction of a green, which represents a very expensive loss.